src/eap_common/eap_fast_common.c

   1 /*
   2  * EAP-FAST common helper functions (RFC 4851)
   3  * Copyright (c) 2008, Jouni Malinen <j@w1.fi>
   4  *
   5  * This software may be distributed under the terms of the BSD license.
   6  * See README for more details.
   7  */
   8
   9 #include "includes.h"
  10
  11 #include "common.h"
  12 #include "crypto/sha1.h"
  13 #include "crypto/tls.h"
  14 #include "eap_defs.h"
  15 #include "eap_tlv_common.h"
  16 #include "eap_fast_common.h"
  17
  18
  19 void eap_fast_put_tlv_hdr(struct wpabuf *buf, u16 type, u16 len)
  20 {
  21         struct pac_tlv_hdr hdr;
  22         hdr.type = host_to_be16(type);
  23         hdr.len = host_to_be16(len);
  24         wpabuf_put_data(buf, &hdr, sizeof(hdr));
  25 }
  26
  27
  28 void eap_fast_put_tlv(struct wpabuf *buf, u16 type, const void *data,
  29                              u16 len)
  30 {
  31         eap_fast_put_tlv_hdr(buf, type, len);
  32         wpabuf_put_data(buf, data, len);
  33 }
  34
  35
  36 void eap_fast_put_tlv_buf(struct wpabuf *buf, u16 type,
  37                                  const struct wpabuf *data)
  38 {
  39         eap_fast_put_tlv_hdr(buf, type, wpabuf_len(data));
  40         wpabuf_put_buf(buf, data);
  41 }
  42
  43
  44 struct wpabuf * eap_fast_tlv_eap_payload(struct wpabuf *buf)
  45 {
  46         struct wpabuf *e;
  47
  48         if (buf == NULL)
  49                 return NULL;
  50
  51         /* Encapsulate EAP packet in EAP-Payload TLV */
  52         wpa_printf(MSG_DEBUG, "EAP-FAST: Add EAP-Payload TLV");
  53         e = wpabuf_alloc(sizeof(struct pac_tlv_hdr) + wpabuf_len(buf));
  54         if (e == NULL) {
  55                 wpa_printf(MSG_DEBUG, "EAP-FAST: Failed to allocate memory "
  56                            "for TLV encapsulation");
  57                 wpabuf_free(buf);
  58                 return NULL;
  59         }
  60         eap_fast_put_tlv_buf(e,
  61                              EAP_TLV_TYPE_MANDATORY | EAP_TLV_EAP_PAYLOAD_TLV,
  62                              buf);
  63         wpabuf_free(buf);
  64         return e;
  65 }
  66
  67
  68 void eap_fast_derive_master_secret(const u8 *pac_key, const u8 *server_random,
  69                                    const u8 *client_random, u8 *master_secret)
  70 {
  71 #define TLS_RANDOM_LEN 32
  72 #define TLS_MASTER_SECRET_LEN 48
  73         u8 seed[2 * TLS_RANDOM_LEN];
  74
  75         wpa_hexdump(MSG_DEBUG, "EAP-FAST: client_random",
  76                     client_random, TLS_RANDOM_LEN);
  77         wpa_hexdump(MSG_DEBUG, "EAP-FAST: server_random",
  78                     server_random, TLS_RANDOM_LEN);
  79
  80         /*
  81          * RFC 4851, Section 5.1:
  82          * master_secret = T-PRF(PAC-Key, "PAC to master secret label hash",
  83          *                       server_random + client_random, 48)
  84          */
  85         os_memcpy(seed, server_random, TLS_RANDOM_LEN);
  86         os_memcpy(seed + TLS_RANDOM_LEN, client_random, TLS_RANDOM_LEN);
  87         sha1_t_prf(pac_key, EAP_FAST_PAC_KEY_LEN,
  88                    "PAC to master secret label hash",
  89                    seed, sizeof(seed), master_secret, TLS_MASTER_SECRET_LEN);
  90
  91         wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: master_secret",
  92                         master_secret, TLS_MASTER_SECRET_LEN);
  93 }
  94
  95
  96 u8 * eap_fast_derive_key(void *ssl_ctx, struct tls_connection *conn, size_t len)
  97 {
  98         u8 *out;
  99
 100         out = os_malloc(len);
 101         if (out == NULL)
 102                 return NULL;
 103
 104         if (tls_connection_get_eap_fast_key(ssl_ctx, conn, out, len)) {
 105                 os_free(out);
 106                 return NULL;
 107         }
 108
 109         return out;
 110 }
 111
 112
 113 int eap_fast_derive_eap_msk(const u8 *simck, u8 *msk)
 114 {
 115         /*
 116          * RFC 4851, Section 5.4: EAP Master Session Key Generation
 117          * MSK = T-PRF(S-IMCK[j], "Session Key Generating Function", 64)
 118          */
 119
 120         if (sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
 121                        "Session Key Generating Function", (u8 *) "", 0,
 122                        msk, EAP_FAST_KEY_LEN) < 0)
 123                 return -1;
 124         wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (MSK)",
 125                         msk, EAP_FAST_KEY_LEN);
 126         return 0;
 127 }
 128
 129
 130 int eap_fast_derive_eap_emsk(const u8 *simck, u8 *emsk)
 131 {
 132         /*
 133          * RFC 4851, Section 5.4: EAP Master Session Key Genreration
 134          * EMSK = T-PRF(S-IMCK[j],
 135          *        "Extended Session Key Generating Function", 64)
 136          */
 137
 138         if (sha1_t_prf(simck, EAP_FAST_SIMCK_LEN,
 139                        "Extended Session Key Generating Function", (u8 *) "", 0,
 140                        emsk, EAP_EMSK_LEN) < 0)
 141                 return -1;
 142         wpa_hexdump_key(MSG_DEBUG, "EAP-FAST: Derived key (EMSK)",
 143                         emsk, EAP_EMSK_LEN);
 144         return 0;
 145 }
 146
 147
 148 int eap_fast_parse_tlv(struct eap_fast_tlv_parse *tlv,
 149                        int tlv_type, u8 *pos, size_t len)
 150 {
 151         switch (tlv_type) {
 152         case EAP_TLV_EAP_PAYLOAD_TLV:
 153                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: EAP-Payload TLV",
 154                             pos, len);
 155                 if (tlv->eap_payload_tlv) {
 156                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 157                                    "EAP-Payload TLV in the message");
 158                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 159                         return -2;
 160                 }
 161                 tlv->eap_payload_tlv = pos;
 162                 tlv->eap_payload_tlv_len = len;
 163                 break;
 164         case EAP_TLV_RESULT_TLV:
 165                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Result TLV", pos, len);
 166                 if (tlv->result) {
 167                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 168                                    "Result TLV in the message");
 169                         tlv->result = EAP_TLV_RESULT_FAILURE;
 170                         return -2;
 171                 }
 172                 if (len < 2) {
 173                         wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
 174                                    "Result TLV");
 175                         tlv->result = EAP_TLV_RESULT_FAILURE;
 176                         break;
 177                 }
 178                 tlv->result = WPA_GET_BE16(pos);
 179                 if (tlv->result != EAP_TLV_RESULT_SUCCESS &&
 180                     tlv->result != EAP_TLV_RESULT_FAILURE) {
 181                         wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Result %d",
 182                                    tlv->result);
 183                         tlv->result = EAP_TLV_RESULT_FAILURE;
 184                 }
 185                 wpa_printf(MSG_DEBUG, "EAP-FAST: Result: %s",
 186                            tlv->result == EAP_TLV_RESULT_SUCCESS ?
 187                            "Success" : "Failure");
 188                 break;
 189         case EAP_TLV_INTERMEDIATE_RESULT_TLV:
 190                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Intermediate Result TLV",
 191                             pos, len);
 192                 if (len < 2) {
 193                         wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
 194                                    "Intermediate-Result TLV");
 195                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 196                         break;
 197                 }
 198                 if (tlv->iresult) {
 199                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 200                                    "Intermediate-Result TLV in the message");
 201                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 202                         return -2;
 203                 }
 204                 tlv->iresult = WPA_GET_BE16(pos);
 205                 if (tlv->iresult != EAP_TLV_RESULT_SUCCESS &&
 206                     tlv->iresult != EAP_TLV_RESULT_FAILURE) {
 207                         wpa_printf(MSG_DEBUG, "EAP-FAST: Unknown Intermediate "
 208                                    "Result %d", tlv->iresult);
 209                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 210                 }
 211                 wpa_printf(MSG_DEBUG, "EAP-FAST: Intermediate Result: %s",
 212                            tlv->iresult == EAP_TLV_RESULT_SUCCESS ?
 213                            "Success" : "Failure");
 214                 break;
 215         case EAP_TLV_CRYPTO_BINDING_TLV:
 216                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Crypto-Binding TLV",
 217                             pos, len);
 218                 if (tlv->crypto_binding) {
 219                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 220                                    "Crypto-Binding TLV in the message");
 221                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 222                         return -2;
 223                 }
 224                 tlv->crypto_binding_len = sizeof(struct eap_tlv_hdr) + len;
 225                 if (tlv->crypto_binding_len < sizeof(*tlv->crypto_binding)) {
 226                         wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
 227                                    "Crypto-Binding TLV");
 228                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 229                         return -2;
 230                 }
 231                 tlv->crypto_binding = (struct eap_tlv_crypto_binding_tlv *)
 232                         (pos - sizeof(struct eap_tlv_hdr));
 233                 break;
 234         case EAP_TLV_REQUEST_ACTION_TLV:
 235                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: Request-Action TLV",
 236                             pos, len);
 237                 if (tlv->request_action) {
 238                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 239                                    "Request-Action TLV in the message");
 240                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 241                         return -2;
 242                 }
 243                 if (len < 2) {
 244                         wpa_printf(MSG_DEBUG, "EAP-FAST: Too short "
 245                                    "Request-Action TLV");
 246                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 247                         break;
 248                 }
 249                 tlv->request_action = WPA_GET_BE16(pos);
 250                 wpa_printf(MSG_DEBUG, "EAP-FAST: Request-Action: %d",
 251                            tlv->request_action);
 252                 break;
 253         case EAP_TLV_PAC_TLV:
 254                 wpa_hexdump(MSG_MSGDUMP, "EAP-FAST: PAC TLV", pos, len);
 255                 if (tlv->pac) {
 256                         wpa_printf(MSG_DEBUG, "EAP-FAST: More than one "
 257                                    "PAC TLV in the message");
 258                         tlv->iresult = EAP_TLV_RESULT_FAILURE;
 259                         return -2;
 260                 }
 261                 tlv->pac = pos;
 262                 tlv->pac_len = len;
 263                 break;
 264         default:
 265                 /* Unknown TLV */
 266                 return -1;
 267         }
 268
 269         return 0;
 270 }